Transplacental transport of fluoride, calcium and magnesium.

ABSTRACT

Background: In fluorosis endemic area, the amount of fluoride transferred to the fetus is significant in determining the early onset of fluorosis. The role played by placenta in transporting fluoride and other ions which are present in high concentrations in the local drinking water is studied. Aims & Objectives: The aim of the present study is to decipher the role of placenta in transport of fluoride to the fetus and to analyze the placental binding & distribution of fluoride, calcium and magnesium within the placenta. Materials & Methods: 200 healthy pregnant women aged between 17- 28 yrs were inducted in the study. All the women had a normal & uneventful delivery. The maternal blood, cord blood & placenta were collected immediately after delivery. The placenta was divided into 3 parts- the maternal side, fetal side & the peripheral. Separate tissue extracts were prepared from each site and analyzed. Fluoride, calcium and magnesium were quantified from the samples. Results: The average drinking water fluoride was 1.64±0.49ppm and ground water fluoride was 10.94±2.09ppm. Fluoride concentration of placenta on the maternal side was 1.62±0.787 ppm and in the periphery it was2.54±1.54 ppm (p<0.001) while that of the fetal side of placenta was1.41±0.776 ppm. Maternal and cord blood fluoride levels were1.21±0.79ppm and 0.45±0.304 ppm respectively (p<0.001). The concentrations of calcium in the maternal blood and cord blood were 9.67±1.53mg% and 9.89±1.89 mg% respectively (P<0. 5). The levels of calcium in the placenta were 8.79±1.36 mg%, 9.68±1.69 mg%, 13.87±3.32 mg% respectively on the maternal surface, fetal surface and periphery (p<0.001). The magnesium concentration on the peripheral part of placenta was twofold higher than that of the maternal serum and cord serum (p<0.001) indicating a significant accumulation of magnesium on the peripheral parts of the placenta. However, the differences in the magnesium concentrations of the placenta on the maternal and fetal surfaces with that of the maternal and cord blood sera were found to be insignificant. Conclusion: The results show that, Fluoride, Calcium and Magnesium accumulate in placenta, with the highest concentration being in the marginal part. The placenta therefore acts as a barrier to the transport of fluoride ions and protects against early fluorosis.